diff --git a/assignments/a4/a4.tex b/assignments/a4/a4.tex
index baef30d..2a73d4a 100644
--- a/assignments/a4/a4.tex
+++ b/assignments/a4/a4.tex
@@ -41,8 +41,8 @@ We need to prove: $1 | (a + kn) \land 1 | n \land (\forall e \in \N, e | (a + kn
 
 \begin{enumerate}
     \item[1.] Proving for: $1 | (a + kn)$ \\
-        That is: $\exists k \in \Z$ s.t. $(a + kn) = 1 \cdot k$ \\
-        Take $k = (a + kn)$ \\
+        That is: $\exists c \in \Z$ s.t. $(a + kn) = 1 \cdot c$ \\
+        Take $c = (a + kn)$ \\
         $(a + kn) = 1 \cdot (a + kn)$ is true.
     
     \item[2.] $1 | n$ is given to be true.